The present era has seen an unprecedented fragmentation of the public sphere, a breakup of public imperium into separate pieces, not only left in the hands of supranational or subnational authorities, but also entrusted to private actors. With the abandonment of previously undisputed notions of strict legal verticality and the undivided general interest, the separation of powers doctrine as applied in most European systems of administrative law is in need of serious rethinking. Current debates on the judicial control of governmental discretion are still hampered by a discursive language and a legal grammar that tend to draw sharp lines between law and policy, awarding each of the three branches of government its own well-defined domain. Contrary to widespread belief, the trias politica as an ideology of disjointed powers and separate spheres cannot be traced back to Montesquieu's theory of law, but only from its philosophical rebuttal and inaccurate reception in subsequent times. Ironically, a proper analysis of Montesquieu's theory may indicate a viable way forward for a system of review of government actions that attunes to its modern social and institutional context.